1. Field of the Invention
The present invention relates to a vehicle bumper device of an automobile, a truck, and the like.
2. Description of the Related Art
Conventionally, in a large vehicle is known a vehicle bump-from-behind buffer device, which is characterized in that with preparing for a bump-from-behind of a following vehicle (car and the like), a rear bumper of the large vehicle is supported so as to be movable forward/backward and a hydraulic buffer for absorption of collision energy for energizing the rear bumper toward a rear of the large vehicle and an actuator for variably regulating a position of the rear bumper, resisting an energizing force of the hydraulic buffer, are provided (see paragraphs 0019 to 0026 and FIGS. 10 and 11 in Japanese Utility Model Patent Laid-Open Publication Hei 5-22216). This is something that makes a rear bumper of a vehicle protrude toward a rear of the vehicle, buffers a shock of a collision by a hydraulic buffer of a hydraulic actuator, and thereby absorbs the shock. At a chassis frame are fixed one ends of two hydraulic actuators and at the other ends are fixed the bumper, thereby a hydraulic pressure is supplied to the hydraulic actuators, hydraulic cylinder rods are extended, and thus the bumper is protruded obliquely downward. Thus, because a plunge-in of a bump-from-behind vehicle can be prevented by protruding the bumper obliquely downward and absorption of collision energy can be achieved by the hydraulic actuators, a shock for a passenger can be alleviated.
On the other hand, in a case of head-on collision of a car that is a bump-from-behind vehicle, the longer a nose length of the vehicle, the longer a crash stroke. Therefore, because a vehicle whose nose length is long can sufficiently achieve the absorption of the collision energy, a shock for a passenger can be alleviated.
However, considering a function such as easy handling of a vehicle turning, a passenger's space, and the like, the shorter the nose length of a vehicle, the easier the handling; and therefore there is a problem of a discrepancy existing for the thought that the nose length is made long in order to improve an absorption property of the collision energy. In addition, with respect to the absorption property of the collision energy, in a case of a collision from a front of the vehicle there is a problem that if such the hydraulic actuators are built in the vehicle, they remain without being crashed at the time of a collision and thereby become a dead space. Furthermore, in a case of collision of a vehicle from an oblique front there is also a problem that rods of hydraulic actuators of a hydraulic buffer break and thereby the absorption property is not sufficiently ensured.
Consequently, in order to solve such the problems is strongly requested a vehicle bumper device that is arranged at a place where crashed remains of an hydraulic actuator do not become a dead space even at the time of a collision from any of front and rear of a vehicle, wherein a rod of the hydraulic actuator is difficult to break and the absorption property of the collision energy and reliability of the vehicle bumper device are high.